Conventional cruise control systems regulate vehicle speed according to a speed setting that a vehicle operator may set and adjust while driving. Adaptive cruise control systems detect moving objects in the vehicle path, such as preceding vehicles, and provide throttle and brake control, as necessary, to maintain a trailing distance from the preceding vehicle.
A headway, or time gap, between the two vehicles is calculated based upon the vehicle speed and the trailing distance from the preceding vehicle. The calculated information is used to maintain a desired headway between the vehicles based on a preset headway value for the adaptive cruise control system. Thus, the adaptive cruise control system can maintain a varying distance from the preceding vehicle as appropriate for the vehicle speed.
Adaptive cruise control systems can cause the vehicle to throttle or brake when the speed is set until the actual headway with the preceding vehicle corresponds to the present headway value for the adaptive cruise control system. In some cases, the headway setting can be incrementally adjusted by the vehicle operator following setting the speed for the adaptive cruise control system.